1. Field of the Invention
The present invention relates to a portable electronic device such as a portable telephone unit (cellular phone), a PDA, a music replay device or the like, which is equipped with a magnetic recording device such as a HDD (hard disk drive) or the like and with a wireless communication module such as a non contact type IC module or the like.
Priority is claimed on Japanese Patent Applications Nos. 2004-221717 and 2004-222607, both filed Jul. 29, 2004, the contents of which are incorporated herein by reference.
2. Description of Related Art
Recently, there has been proposed a portable telephone unit which is equipped with a non contact type IC module having a wireless communication function, or a portable telephone unit to which is detachably mounted an IC card equipped with such a non contact type IC module, and such devices have been partially implemented. Such a non contact type IC module may have, for example, a function of acting as a train ticket or season ticket, an electronic money function, a prepaid function, a personal identification function, or the like.
It is possible to perform, for example, ticket examination automatically by using the portable telephone unit which includes such a non contact type IC module. This is accomplished by data transmission and reception performed via wireless communication by the user presenting his portable telephone unit to a read-write section, which performs reading and writing of data, of a data transmitting and receiving device of an automatic ticket examination machine in a train station. It is also possible for the user, when purchasing goods, to pay the price of the goods by performing wireless communication by using his portable telephone unit which includes such a non contact type IC module. In this case, the portable telephone unit communicates with a data transmitting and receiving device which is provided in a shop.
Such a non contact type IC module typically comprises an IC chip (a semiconductor integrated circuit) and an antenna coil. The IC module performs wireless communication with an external data transmitting and receiving device via the antenna coil. The non contact type IC module may be classified into so called passive and active types. In the passive type IC module, magnetism is received from the data transmitting and receiving device, so that electrical power which is generated by electromagnetic induction is supplied to the IC chip as a power source. In the active type IC module, a power source is provided for driving the IC chip.
In recent years, portable telephones have come to require greater and greater memory capacity since a modern portable telephone unit is required to handle voice data, image data, character data and so on in order to respond to demands for high sound quality and high voice quality. However, the type of semiconductor memory which has been conventionally used is high in price, and its capacity is not so very great. Thus, it has been considered to use a HDD (Hard Disk Device) as a storage device because it can perform magnetically reading and writing a very large amount of data at a comparatively cheap price. Recently small sized HDDs have become available, and it has also become possible to incorporate them into portable telephone units (for example, refer to Japanese Unexamined Patent Application, First Publication, No. H09-65268). Accordingly, in the near future, the probability is high that it will be possible to implement a portable telephone unit which incorporates both a non contact type IC module and an HDD.
The case will now be considered in which a user passes, for example, an automatic ticket examination machine with bearing his portable telephone unit which incorporates both the non contact type IC module and the HDD.
A certain amount of magnetism (magnetic force) for generating electrical power by induction is emitted from the read-write section of such an automatic ticket examination machine towards the non contact type IC module. Moreover, the IC module performs wireless communication with the reader-writer via electromagnetic waves. Due to this, there is a possibility that the above described magnetism and electromagnetic waves may exert an influence upon the HDD so that data stored in the HDD may be destroyed, or that erroneous operation of the HDD may occur. This type of possibility is not limited to the case of a portable telephone unit; it may also occur with a different type of portable electronic device, such as a PDA or a music replay device or the like.
Furthermore, the portable telephone unit performs transmission and reception of data in a non contact manner in which its one side where the non contact type IC module is provided is approached near to a data transmitting and receiving device of the automatic ticket examination machine. However, in practice, it often happens that a user may strike the portable telephone unit against the read-write section of the data transmitting and receiving device almost to the extent of colliding it thereagainst while he passes the automatic ticket examination machine. As well known, the HDD performs writing and reading information using a magnetic head which flies with a minute distance above a magnetic disk surface which is rotating at high speed. Accordingly, an extremely accurate mechanism is used in the head mechanism etc. which reads and writes the data. Thus there are the problems that, when the portable telephone unit is struck strongly against the read-write section while the HDD performs reading or writing information, head crashing or the like, or read or write errors may occur in the HDD, so that the destruction of data may take place due to the shock caused thereby. Furthermore, there is also a possibility that the read or write operation of the HDD may be influenced by the above-mentioned magnetism for generation of electrical power via the antenna coil by electromagnetic induction.